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Learn about Secure Origin BGP (s-BGP), a system created by Cisco engineers as a lightweight alternative to BGP security. Discover its certificate types, changes to BGP, processing updates, and other benefits.
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Secure Origin BGP: What is (and isn't) in a name? Dan WendlandtPrinceton Routing Security Reading Group
History • Created by Cisco engineers as a light-weight (computation and PKI) alternative to s-bgp. • Originally only secured “origin” of routes, but topology information added later for additional security. • Goal: A more real-world and usable system
Certificate Types • Entity Cert: Organization -> ASN, Public Key • Policy Cert: ASN -> Neighbors, Security Parameters • Authorization Cert: ASN -> Network Prefixes, meta-data
Changes to BGP • New “Security” Message (ie: updates are not used for security data). • Ability to “ask” neighbor for security certificates. • Authorization, Entity Certificate and Path Database
“Web of Trust” for Public Keys • Root of Entity Cert trust hierarchy is not necessarily ICANN, but instead a group of “well-known entities”. It could also be private entity like Verisign, or a collection of tier-1 ISPs. • Ambiguity with respect to Auth Certs (need ICANN hierarchy or not?)
Origin Auth + Path “Plausibility” • Originating AS's are validated much like s-BGP • AS-Path's are checked plausibility against topology database, not attested with cryptography • Path Check bits in Policy Cert. • Security Preference allows for “fuzzy” match.
Processing Updates • Find Auth Cert for this prefix in local database. • If route is originated by an ASN in the cert, continue, else discard • If path-check bit is set, check that each hop in the AS-PATH exists in both directions in the path database (alternately, just check 1st hop). • Set “security preference” and install in RIB.
Other Benefits • Policy Flexibility (let's you split an update, advertising some prefixes, but not others) • Less verification load vs path attestation (still need crypto hardware though?). • Robustness to gaps in deployment? • Ability to “outsource” certificate validation to servers, provide routers with databases. • Include policy information in certificates (AS X may not transit this route, etc)
Dirty “Little” Issues • Peer links advertised (confidentiality)? • Aggregation • Determining extent of trust propagation within web-of-trust. • Difference between path plausibility and path attestation? • Where is database stored? Memory Issues in keeping AS-level topology? • Incremental Deployment needs multi-hop BGP sessions to participants.
References • ftp://ftp-eng.cisco.com/sobgp/index.html • Extensions to BGP to Support Secure Origin BGP: draft-ng-sobpg-bgp-extensions-01.txt • soBGP Architecture & Deployment: draft-white-sobgp-architecture-01.txt